Homogenizers have a variety of applications and are extensively used in biological, chemical and pharmaceutical research and laboratory testing. Among the uses in research and testing are homogenizing biological tissue, disrupting cell membranes or walls, dispersing solids or powders in liquids, accelerating chemical reactions and preparing emulsions. Homogenizers also can shred, mix, blend and dissolve materials of various kinds.
Those skilled in the art know a homogenizer is a very sophisticated mixer or blender similar in some functions to a household food mixer or blender. Those skilled in the art also know that a homogenizer usually consist of a base, support post, support bracket, motor and homogenizing tool. The base, support post and support bracket securely hold the motor, shaft and homogenizing tool over the container with the sample to be homogenized. The homogenizing tool is located at the bottom end of a shaft extending down from the motor. The homogenizing tool can be raised or lowered by use of the support bracket. Often, but not always, the container in which the item or items to be homogenized are placed is specially made to work in conjunction with a cover or cap attached to the shaft of the homogenizing tool. Consequently, at the same time the homogenizing tool is lowered into the specially made container, the cap or cover comes in contact with the top edge of the mouth of the container. The container, the homogenizing tool and cap are made and arranged so that the cap presses down onto the top edge of the container to hold it in place and center the homogenizing tool in the center of the container during the process of homogenization.
The homogenizing tool can be an open blade assembly or a rotor located in a cylindrical stator both of which are known in the art. The rotor draws the sample to be homogenized up into an opening in the base of the stator and then ejects the sample out through holes in the curved cylindrical surface of the stator. Open flasks, which can be secured by a bracket, can also be used with the homogenizing tools.
There are several disadvantages with the technology described above. Specially made containers must be used that entail added expense and require the transfer of the item or items to be homogenized to the container. Centering of the container to receive the homogenizing tool must be done by hand. Once the cap is secured to the top of the container and homogenizing tool is placed in the container and fully engaged, there is no way to vary the position of the homogenizing tool in the container. The homogenizing tool, when fully engaged, is at the center of the container. This arrangement can lead to "vortexing," an affect where items are thrown to the side and remain there, in particular fibrous material or solids such as powders, consequently, complete homogenization of the material may not be accomplished. Specially made fluted flasks, known in the art, can be used to help eliminate vortexing.
One way to avoid the problem of vortexing and use a standard laboratory container is for the operator to hold the container with the material to be homogenized during the homogenization process. The operator can control the position of the container by manually moving it and thus avoid the problem created by vortexing.
However, manual control of the position of the container by the operator creates several problems. One problem is an inability to center the container precisely when necessary. An even more serious and deadly problem is exposure of the operator to the substances being homogenized that may be hazardous and life threatening. Manual manipulation of the container during the homogenization process could result in spillage or splattering of the items being homogenized onto the operator.
Another problem with homogenizers currently in use is the risk of destroying temperature sensitive samples, such as DNA, during the homogenization process. The heat generated by the homogenizing tool during the homogenizing process can, in some instances, raise the temperature of the material being homogenized above a safe level and cause degradation or destruction of the sample.